Inkjet inks used for drop on demand (DOD) printing need to use low viscosity materials to yield a viscosity of up to approximately 12 cP at jetting temperatures. Monomers have low molecular weight and high vapor pressure. Many of the monomers used in the inkjet inks have distinct odors that can lead to taint when used on secondary or tertiary packaging.
Monomers may have multiple acrylate groups. The higher number of acrylate groups leads to a polymer with a higher degree of cross linking, which reduces odor. A higher degree of cross linking also leads to a faster curing material and a harder material. However, higher cross linking will lead to a more brittle ink which will not be acceptable for application that requires bending of the ink layer without cracking such as in corrugated board where creasing is required.